Sustained release formulation of animal growth hormone and process for preparation thereof

Abstract

The present invention relates to a sustained-release formulation of an animal growth hormone and a process for preparation thereof, comprising a step to produce solid pellets by mixing an animal growth hormone and an excipient in accordance with a direct tabletting method and a step to coat the pellets with a film comprising a biodegradable polymer and a poloxamer. The thus obtained formulation has small initial drug release, and shows a continuous and uniform effect when administered. Further, the formulation of the present invention may be produced economically in a large scale.

What is claimed is: 
     
       1. A sustained-release formulation of an animal growth hormone comprising a solid pellet containing an animal growth hormone and an excipient; and a film composed of a biodegradable polymer and a poloxamer, wherein said film coats said pellet, and wherein the biodegradable polymer is polylactide (PLA), polyglycolide (PGA), poly(lactide-co-glycolide) (PLGA) or a mixture thereof. 
     
     
       2. The formulation of claim 1, wherein the animal growth hormone is bovine somatotropin or porcine somatotropin. 
     
     
       3. The formulation of claim 1, wherein the amount of the animal growth hormone is 20-80 wt % based on the total weight of the formulation. 
     
     
       4. The formulation of claim 1, wherein the excipient is a hydrophilic or hydrophobic material, or a mixture thereof, and the amount thereof is from 20 to 80 wt % based on the total weight of the formulation. 
     
     
       5. The formulation of claim 4, wherein the hydrophilic material is polyethyleneglycol, dextran, pectin, alginic acid, cellulose, gelatin, or a mixture thereof. 
     
     
       6. The formulation of claim 4, wherein the hydrophobic material is paraffin wax, carnauba wax, bees wax, zein, ethylcellulose, or a mixture thereof. 
     
     
       7. The formulation of claim 1, wherein the film comprises a biodegradable polymer and a poloxamer in a ratio ranging from 7:3 to 9:1. 
     
     
       8. A process for the preparation of a sustained-release formulation of an animal growth hormone, which comprises; directly tabletting a powder mixture of an animal growth hormone and an excipient to obtain a solid pellet; coating the pellet with a film composed of a biodegradable polymer and a poloxamer. 
     
     
       9. The process of claim 8, wherein the animal growth hormone is spray-dried. 
     
     
       10. The process of claim 8, wherein the animal growth hormone is freeze-dried.